Many public and private groups, such as security and safety personnel (e.g., police, fire fighters and ambulance drivers) use various communication networks of differing technologies and types for communication. Many networks utilize land mobile radios communicating through push-to-talk technologies. However, communications among different endpoints of different networks such as endpoints of different police, fire or other security networks may be difficult. Collaboration between the different agencies and networks tends to be ad hoc and inefficient. When achieved, it often involves laborious manual intervention. Organizations working towards interoperability solutions include Raytheon JPS Communications, IP Blue, Twisted Pair, M/A-COM and Cisco Systems.
In some systems, dispatchers divide various voice channels into two groups and direct their voice systems to deliver more important channels to their, for example, right ear while the other less important channels are directed to their left ear. Some systems allow users and dispatchers to present voice streams from any desired fixed direction.
U.S. Pat. No. 5,048,082, entitled “Voice direction recognition in a digital telephone station” describes a method for controlling a voice-controlled voice direction recognition unit for a digital telephone. It allows users to alter the direction of arrival of their voice by manipulating the attenuation of the signals to the headset. Some conferencing systems divide conferencing presentation sound fields into sectors and allocate one or more sectors to each conferencing endpoint. These systems allow a conference participant to increase his comprehension when multiple participants are speaking simultaneously, as well as to alleviate confusion as to who is speaking at any given time. Some methods convey GPS information of speakers to listeners and facilitate a presentation of an icon on a map that identifies the location of a speaker.